000 02363nab a2200205 4500
005 20260520000837.0
008 260224s2009 xxu
245 0 0 _aSaccharification and fermentation of dilute-acid-pretreated freeze-dried switchgrass
260 _a
_b
_cnov./dic. 2009
270 _a08/06/2010 ; 08/06/2010
300 _a9 p. ; 5626-5635
520 _aTranscripción del resumen del autor. This study investigated the potential of three freeze-dried switchgrass germplasms (St6-1, St6-3E, and St6-3F) as whole plants or their stems and leaves for bioethanol production. Whole switchgrass germplasms contained 24.34-30.95% glucan, 14.68-18.58% xylan, and 17.39-19.46% lignin. Switchgrass samples were pretreated with dilute sulfuric acid at concentrations of 0.5, 1.0, or 1.5% (w/v) for 30, 45, or 60 min at 121 °C and 15 psi. Although lignin degradation was limited, over 80% hemicellulose solublization was observed, especially in leaf samples, and the removal could be enhanced by increasing the pretreatment intensity through acid concentration and treatment time adjustment. Within each germplasm, pretreated samples with the least lignin content or greatest percent hemicellulose (xylan and arabinan) solublization were hydrolyzed enzymatically by cellulase at 0, 15, or 30 filter paper units (FPU)/g of dry biomass supplemented with cellobiase. Although the addition of cellulase greatly improved cellulose to glucose conversion, no significant (p = 0.05) differences were observed between activity levels of 15 and 30 FPU/g of dry biomass. Pretreatment significantly (p < 0.05) improved cellulose conversion in samples with the greatest hemicellulose solublization; complete cellulose hydrolysis was observed in some St6-3F samples. Fermentation of hydrolyzates with Saccharomyces cerevisiae (ATCC 24859) resulted in the greatest ethanol yield of 0.083 g of ethanol/g of raw St6-3F switchgrass whole plant, which was 60% of the theoretical yield. Results from this study demonstrated the potential of new switchgrass germplasms as energy crops for bioethanol production through dilute sulfuric acid pretreatment.
581 _a6
773 0 _tEnergy & fuels
_g23
942 _cARTICULO
100 1 _aSharma-Shivappa, Ratna R.
_942305
100 1 _aYang, Ying
_942306
100 1 _aBurns, Joseph C.
_942307
999 _c170799
_d170799